net: Add a layer for non-PHY MII time stamping drivers.

While PHY time stamping drivers can simply attach their interface
directly to the PHY instance, stand alone drivers require support in
order to manage their services.  Non-PHY MII time stamping drivers
have a control interface over another bus like I2C, SPI, UART, or via
a memory mapped peripheral.  The controller device will be associated
with one or more time stamping channels, each of which sits snoops in
on a MII bus.

This patch provides a glue layer that will enable time stamping
channels to find their controlling device.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 63 insertions, 0 deletions

diff --git a/include/linux/mii_timestamper.h b/include/linux/mii_timestamper.h
index 36002386029c..fa940bbaf8ae 100644
--- a/include/linux/mii_timestamper.h
+++ b/include/linux/mii_timestamper.h
@@ -33,10 +33,15 @@ struct phy_device;
  *		the phy_device mutex.
  *
  * @ts_info:	Handles ethtool queries for hardware time stamping.
+ * @device:	Remembers the device to which the instance belongs.
  *
  * Drivers for PHY time stamping devices should embed their
  * mii_timestamper within a private structure, obtaining a reference
  * to it using container_of().
+ *
+ * Drivers for non-PHY time stamping devices should return a pointer
+ * to a mii_timestamper from the probe_channel() callback of their
+ * mii_timestamping_ctrl interface.
  */
 struct mii_timestamper {
 	bool (*rxtstamp)(struct mii_timestamper *mii_ts,
@@ -53,6 +58,64 @@ struct mii_timestamper {
 
 	int  (*ts_info)(struct mii_timestamper *mii_ts,
 			struct ethtool_ts_info *ts_info);
+
+	struct device *device;
+};
+
+/**
+ * struct mii_timestamping_ctrl - MII time stamping controller interface.
+ *
+ * @probe_channel:	Callback into the controller driver announcing the
+ *			presence of the 'port' channel.  The 'device' field
+ *			had been passed to register_mii_tstamp_controller().
+ *			The driver must return either a pointer to a valid
+ *			MII timestamper instance or PTR_ERR.
+ *
+ * @release_channel:	Releases an instance obtained via .probe_channel.
+ */
+struct mii_timestamping_ctrl {
+	struct mii_timestamper *(*probe_channel)(struct device *device,
+						 unsigned int port);
+	void (*release_channel)(struct device *device,
+				struct mii_timestamper *mii_ts);
 };
 
+#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
+
+int register_mii_tstamp_controller(struct device *device,
+				   struct mii_timestamping_ctrl *ctrl);
+
+void unregister_mii_tstamp_controller(struct device *device);
+
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+						 unsigned int port);
+
+void unregister_mii_timestamper(struct mii_timestamper *mii_ts);
+
+#else
+
+static inline
+int register_mii_tstamp_controller(struct device *device,
+				   struct mii_timestamping_ctrl *ctrl)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void unregister_mii_tstamp_controller(struct device *device)
+{
+}
+
+static inline
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+						 unsigned int port)
+{
+	return NULL;
+}
+
+static inline void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
+{
+}
+
+#endif
+
 #endif